Planetary washing machine drive with centrifugal clutch

ABSTRACT

The invention relates to a washing machine drive which comprises a motor and a planetary gear set. In operation the drive is switched from a washing speed to a spinning speed by clutch and brake means having two stages. The clutch means for maintaining the washing speed are associated with centrifugal weights and these brake means do not release until moments after the clutch means for the spinning speed is actuated. The main object is to avoid a mode of operation which involves a sudden pronounced change in the load which has a harmful effect on the machine.

United States Patent Kjeldsteen Mar. 19, 1974 1 PLANETARY WASHINGMACHINE DRIVE WITH CENTRIFUGAL CLUTCH [75] Inventor: Per Kjeldsteen,Nordborg, Denmark [73] Assignee: Danioss A/S, Nordborg, Denmark [22]Filed: June 2, 1972 [21] Appl. No.: 259,114

[30] Foreign Application Priority Data June 8. 1971 Germany 2128418 [52]US. Cl..v 74/752 E, 192/4 C [51] Int. Cl. Fl6h 5/46 [58] Field of Search74/752 E; 192/4 C [56] References Cited 1 UNITED STATES PATENTS1.416.996 5/1922 Stucaturl 74/752 E 1.738.201 12/1929 Persons I 74/752 E1.931.756 10/1933 Duesenberg I 74/752 E 1.969.683 8/1934 Berry' I 74/752E 2.011.101 8/1935 Dodge 74/752 E 2.151.151 3/1939 Perez 74/752 E111/1939 Enson H 192/4 C 2.597354 5/1952 Cross C1311. I 74/752 E2.649.817 8/1953 Lu Vogue 74/752 E X 2.836.046 5/1953' Smith 74/752 F. X2.924.997 2/1961) Rodler. Jr. 74/752 Primary Examiner-Benjamin W. WycheAssistant Examiner-J. Reep [57] ABSTRACT 5 Claims, 4 Drawing FiguresPATENTEDHARISIBM 3.791331 sum 1 [1F 2 PATENTEDHAR19 m4 3.797.331 'SHEU 2BF 2 PLANETARY WASHING MACHINE DRIVE WITH CENTRIFUGAL CLUTCH Theinvention relates to a washing machine drive comprising a motor and aplanetary gear which can be switched from a washing speed to a spinningspeed by means of a combination brake and clutch device, which comprisesa disc which is connected to parts of the gear and which, when displacedby means of an actuating element, is connectible to non-revolving partsthrough a friction brake and to revolving parts of the gear through afriction clutch.

Washing machine drives of this kind are known in which the disc has twofriction surfaces, one of which can be coupled to a friction surfacesolid with the easing, whilst the other, after an axial displacement,can be coupled to a friction surface which revolves with the driveshaft. The first friction clutch imparts a slow washing speed to theoutput shaft, and the second clutch provides a more rapid speed forspinning.

In the known washing machine drives the two clutches are optionallyengaged. Switching from the clutch for the spinning operation to thatfor the washing operation in particular leads to sudden and pronouncedchanges in load which have a harmful effect upon the gear and otherparts of the machine. Moreover, considerable time elapses before thedrum of the washing machine reaches the washing speed, or comes to astop when the machine is switched off, although the clutch disc isbrought into contact with parts that are prevented from rotating. r r

The object of the invention is to provide a washing machine drive of theinitially stated kind in which slowing down takes place in a smoothermanner when the machine is switched off during the spinning operation.

According to the invention, this object is achieved by As long as bothclutches are effective, not only is that part of the planetary gear thateffects reduction slowed down, but also the-entire arrangementconsisting of the drive shaft, possibly with the motor connectedupstream thereof, of the planetary gear switched to high speed runningand of the output shaft carrying the drum of the machine..This leads toa very gentle braking action. Despite the smooth slowing down, thewashing speed or, when the machine is switched off, stoppage of the drumis reached within a short time. The change over from the spinning speedto the washing speed requires less than 5 seconds, andfor example only 2seconds. Since the locking device operates in dependence upon speed, thesecond clutch is disengaged as soon as a predetermined sufficiently lowspeed is reached.

In a preferred arrangement, the clutch disc carries centrifugal weightsto which are fitted substantially axially parallel friction faces of thesecond clutch, and when the first clutch is engaged, theactuatingelement applies to the weights predetermined radial forcesacting in the direction opposite to that of the centrifugal force. Afterthe first clutch is engaged the second clutch therefore remains inengagement until the radial forces applied by the actuating elementovercome the centrifugal forces that are dependent upon speed.

Also a spreader spring may urge the centrifugal weights outwards, andthe actuating element, upon engagement of the first clutch, can beloaded by springs, the radial force component of which is greater thanthat of the spreader spring. The spreader spring ensures that the secondclutch is always engaged when the actuating element is not applyingradial forces. The difference between these radial forces and the forceapplied by the spreader spring is then that effective radial force thatcounteracts the speed-responsive centrifugal force. The force applied bythe spreader spring can be small; it has only to ensure that the secondclutch is able to transmit a certain initial moment of rotation. Thegreater the speed, the greater is the moment of rotation to betransmitted by the clutch, as a consequence of the centrifugal 'force.

In a very simple arrangement, the actuating element is secured againstrotation and acts on the centrifugal weights through at least some ofthe friction faces forming the first clutch. As long as the actuatingelement engages these centrifugal weights the required braking action isachieved.

Furthermore, the actuating element may be axially displaceable and mayact on the centrifugal weights through tapered portions of the frictionface. The axial movement of the actuating element can be readilycontrolled and the pressure of the first clutch is also clearly definedthereby. Moreover, the required radial force is produced by the taperedfriction face.

In particular, the actuating element may be an annular magnet armaturewhich has a frustoeonical outer periphery and which, when the magnet isde-energiz ed, cooperates with the centrifugal weights. An armature ofthis kind can be readily displaced in the axial direc tion. It releasesthe centrifugal weight when the magnet is energized, so that the clutchfor the spinning operation can be engaged. The armature can be biased inthe opposite direction by axial springs, so that the frustoconicalperiphery applies force to the. centrifugal weights in the axialdirection for the purpose of achieving a braking action, and appliesforce tothe weights in the radial, direction to overcome the centrifugalforce. i

A particularly favourable. arrangement is achieved if the clutch disc isaxially displaceable under the action of the actuating element, if thefirst clutch is divided into a brake clutch and into aclutch for thewashing operation that only engages upon completion of the axialdisplacement of the clutch disc, and if the locking device preventsaxial displacement of the clutch disc until the second clutch isdisengaged. In such arrangement the first and second clutches can beprecisely de signed to suit their operating conditions. When the twoclutches are simultaneously effective however, only part of the firstclutch is in operation. This part can be of such size that it providesanoptimum braking performance with respect to the second clutch.

Generally, the frictional forces of the second clutch that occur betweenthe friction faces suffice to delay axial displacement until apredetermined moment is reached. Greater operational reliability isachieved if the friction faces of the second clutch are slightlyinclined, preferably at approximately 2, to the axis and towards theclutch for the washing operation. This inclined position also offersthe'advantage that the clutch disc is automatically returned in theaxial direction to its initial position when the centrifugal force isset up.

Particularly good results have been achieved in an arrangement in whichthe clutch disc is a carrier for planetary gearwheels. This results in avery simple construction.

Furthermore, the journals for the planetary gearwheels can also serve aspivot pins for the centrifugal weights.

Broadly, a washing machine drive is provided which can occupy any one ofthree operating positions, i.e., for the washing operation, for thespinning operation and for braking, although the actuating element, i.e.a magnet armature in particular, can be moved into only two workingpositions.

The invention will now be described in greater detail by reference to anembodiment illustrated in the drawing, in which:

FIG. 1 is a longitudinal section through part of that end of a drivemotor for a washing machine that comprises a gear, the clutch beingshown in the position for the spinning operation.

FIG. 2 is a cross-section on the line AA of FIG. 1,

FIG. 3 is a portion from FIG. 1, in which the clutch is shown in theposition for the washing operation, and

FIG. 4 is a similar illustration in which the clutch is shown in theposition for braking.

An electric motor comprising a stator 2 with a stator winding 3 and arotor 4 with a short-circuited winding 5, is accommodated in ahousing 1. The rotor drives the shaft 6 supported at each of the twoends of the motor. Through a sleeve 7, the shaft 6 drives a disc 8,having a coupling flange 9, and a sunwheel 10 of a planetary gear 11.Through planetary gearwheels 12, the latter engages an outer ring 13which contains a V-groove 14 for receiving a drive belt for the drum ofthe washing machine. The planetary gear is covered by a protective cap15. r I

The planetary gearwheels 12 rotate on journals 16 which are secured in acarrier 17 also referred to here-. inafter as the brake disc.

An annular electro-magnet 18 having a winding 19 is fitted in thehousing 1. The magnet can pull up an annular armature 20 which has afrustoconical flange 21 which is guided at its outer portion on pins 22and is biased in the direction opposite that of the magnetic force by aspring 23 acting in the axial direction. The housing is closed off by acoverplate 24 which comprises an inclined brake face 25.

Two centrifugal weights 26 and 27 are provided on the brake disc 17.They are adapted to rotate about extensions 28 and 29 of pivot pins 16on which they are secured with the aid of clamping rings 30. For thepurpose of explaining the invention in a better manner, in FIG. 1 thecentrifugal weights and the associated parts are displaced from theirpositions as shown in FIG. 2. Each centrifugal weight 26 and 27 isbiased outwardly by spreader springs 31. Pins 32 limit the inwardmovement of the centrifugal weights 26 and 27 by bearing against stops33. Each centrifugal weight carries a brake lining 25 on its inner arm34 and a brake lining 37 on its outer arm 36. Also, the brake disc 17carries a brake lining 39 on a radial arm 38. The following brakesystems are therefore created:

l. A first brake between the brake disc 17, or the parts connectedthereto, and parts which are secured against rotation. This first brakeis divided into a. A brake which is formed by the frustoconicalperiphery 21 of the armature and the brake lining 37. The brake face isdisposed at an angle of approximately 30 to the axis of the shaft.

b. A clutch for the washing operation which consists of the inclinedface and the brake lining 39. The brake face is inclined to the axis ofthe shaft likewise at about but in the opposite direction.

2. A clutch for the spinning action which consists of the clutch flange9 and the clutch lining 35. The

clutch face is inclined at an angle of approximately 2 to the axis ofthe shaft on the side opposite the motor.

The operating conditions in the three characteristic operating positionswill now be described by reference to FIGS. 1, 3 and 4.

FIG. 3 illustrates how the machine operates at washing speed. The clutch9, 35, i.e. the clutch for the spinning operation, is disengaged, andthe brake consisting of the brake 21, 37 and the clutch 25, 39 for thewashing action is engaged. This is achieved by means of the spring 23which urges the armature 20 to the right and thus not only applies anaxial load to the clutches 21, 37 and the brakes 25, 39, but also urgesthe centrifugal weight 26 inwards, thereby overcoming the force Fexerted by the spreader spring 31. The brake disc 17 stops. The speed ofthe sunwheel 10, reduced by the planetary wheels 12, is transmitted bythese wheels to the outer ring 13. The latter therefore rotates slowly.

FIG. 1 illustrates how the drive operates during the spinning action ofthe machine. Here the clutch 9, is engaged, whereas the brake 21, 37 andthe clutch 25, 39 are disengaged. For this purpose the armature 20.ispulled up by the magnet 18. Consequently the spreader springs 31 apply aforce F to the centrifugal weights 26 and urge them outwards until theclutch 9, 35 engages. However, when the brake disc 17 rotates at thesame speed as the shaft 6 as a result of connection through the disc 8,the outer ring 13 also assumes the same speed as the shaft 6. The outputspeed is correspondingly high. Here it suffices for the spreading forceF of the springs 31 to be great enough to result in a certain degree ofacceleration of the brake disc 17, since as the speed rises centrifugalforces are set up which increase the moment of rotation that can betransmitted. Since the clutch face of the clutch 9, 35 is slightlyinclined to the shaft 6, the brake disc 17 is drawn axially to the leftso that the brake 25, 39 can be disengaged in a better manner.

FIG. 4 shows the position when the machine is switched to spinningspeed. The magnet 18 is deenergized, and the armature 20 is againpressed to the right by the spring 23. When this happens, the edge 21strikes the brake lining 37. Since, because of the high spinning speeds,the centrifugal arms 26 and 27 cannot move inwards, a braking actionoccurs at the brake 21, 37. Simultaneously, however, the clutch 9, 35,also becomes operative. Consequently the braking force is transmitteddirectly to the drive shaft and, on account of the locking action of theplanetary gear, also to the outer ring 13. The brake faces 21, 37 andclutch 9, 35 are so matched that a gentle but efficient grabbingactiontakes place during which slip occurs in both sets of relatively movablemembers. After the speed has dropped below a predetermined level, thesum of the force F applied by the spreader springs 31 and thecentrifugal force no longer suffices to overcome the radial component ofthe force applied by the springs 23. The clutch 9, 35 begins todisengage. At a position which is determined by the nature andinclination of the clutch faces, the axial force applied by the springs23 overcomes the axial holding force of the brake 9, 35, and the clutchdisc 17 is displaced axially to the right so that the brake 25, 39 forthe washing operation is also engaged. Brake faces of considerable sizeare now available for receiving the moments of rotation that occur.

The centrifugal weights can also be formed by radially guided parts.Division of the brake and clutch means into twoparts 21, 37 and 25, 39is not essential. Instead of an axially movable actuating element 20,use may also be made of a circumferential strip which is contractedunder a predetermined force and thus applies definite radial forces.

The idea underlying the invention canalso be applied to other knownkinds of planetary gears for washing machines. However, the use of agear which is disposed in a single plane and comprises an outer ringsupplying the output capacity is recommended on account of the compactconstruction in the axial direction.

I claim:

l. A washing machine drive comprising a casing, a motor, a planetarygear set having speed changing elements, a drive shaft between saidmotor and said planetary gear set, a brake disk connected to one of saidelements for rotation therewith, selectively operable brake meansbetween said brake disk and said casing, and speed responsiveautomatically operable clutch means between said brake disk and saiddrive shaft which maintains a centrifugal force oriented clutchingengagement momentarily after a braking engagement is initiated for saidselectively operable brake means, said brake disk carrying centrifugalweight means, said automatically operable clutch means being betweensaid centrifugal weight means and said drive shaft, brake parts of saidselectively operable brake means and clutch parts of said automaticallyoperable clutch means being on said centrifugal weight means, said brakeand clutch parts having the form of radially spaced apartcircumferential segments.

2. A washing machine drive according to claim 1 including a magneticallyoperable actuator which is axially movable relative to said casing, abrake portion of said selectively operable brake means being carried bysaid actuator, actuator spring means for biasing said ac tuator intoclutching engagement with said centrifugal weight means, centrifugalweight spring means between said brake disk and said centrifugal weightmeans for biasing said centrifugal weight means into effective clutchingengagement with said drive shaft, said actuator spring means exerting alarger biasing force than said centrifugal weight spring means.

3. A washing machine drive according to claim 1 including a magneticallyoperable actuator which is axially movable relativeto said casing, abrake portion of said selectively operable brake means being carried bysaid actuator, said brake disk being axially movable, third brake meansbetween said brake disk'and said casing, said third brake means beingoperated by an ef fective biasing engagement between said brake disk andsaid magnetically operated actuator only subsequently to thedisengagement of said automatically operable clutch means.

4. A washing machine drive according to claim 1 wherein said brake diskis a carrier element for said planetary gear set.

5. A washing machine drive according to claim 1 wherein said centrifugalweight means are pivotally mounted, said planetary gear set includingplanetary gear wheels and, journals between said gear wheelsand saidclutch disk, said centrifugal weight means being pivotally mounted onsaid journals.

1. A washing machine drive comprising a casing, a motor, a planetarygear set having speed changing elements, a drive shaft between saidmotor and said planetary gear set, a brake disk connected to one of saidelements for rotation therewith, selectively operable brake meansbetween said brake disk and said casing, and speed responsiveautomatically operable clutch means between said brake disk and saiddrive shaft which maintains a centrifugal force oriented clutchingengagement momentarily after a braking engagement is initiated for saidselectively operable brake means, said brake disk carrying centrifugalweight means, said automatically operable clutch means being betweensaid centrifugal weight means and said drive shaft, brake parts of saidselectively operable brake means and clutch parts of said automaticallyoperable clutch means being on said centrifugal weight means, said brakeand clutch parts having the form of radially spaced apartcircumferential segments.
 2. A washing machine drive according to claim1 including a magnetically operable actuator which is axially movablerelative to said casing, a brake portion of said selectively operablebrake means being carried by said actuator, actuator spring means forbiasing said actuator into clutching engagement with said centrifugalweight means, centrifugal weight spring means between said brake diskand said centrifugal weight means for biasing said centrifugal weightmeans into effective clutching engagement with said drive shaft, saidactuator spring means exerting a larger biasing force than saidcentrifugal weight spring means.
 3. A washing machine drive according toclaim 1 including a magnetically operable actuator which is axiallymovable relative to said casing, a brake portion of said selectivelyoperable brake means being carried by said actuator, said brake diskbeing axially movable, third brake means between said brake disk andsaid casing, said third brake means being operated by an effectivebiasing engagement between said brake disk and said magneticallyoperated actuator only subsequently to the disengagement of saidautomatically operable clutch means.
 4. A washing machine driveaccording to claim 1 wherein said brake disk is a carrier element forsaid planetary gear set.
 5. A washing machine drive according to claim 1wherein said centrifugal weight means are pivotally mounted, saidplanetary gear set including planetary gear wheels and journals betweensaid gear wheels and said clutch disk, said centrifugal weight meansbeing pivotally mounted on said journals.